In general, a modified asphalt means an asphalt which exhibits improved impact resistance, elasticity, flexibility, waterproofing property, storage stability and the like by mixing the asphalt with a polymer modifying agent such as a styrene-butadiene block copolymer.
However, disadvantageously, the modified asphalt is volatile under continuous low temperature conditions and thus causes cracking, it has degraded storage stability when the content of modifying agent or the molecular weight of polymer is increased for improvement of physical properties and it has low workability upon modification due to slightly high viscosity.
Accordingly, there is a need for development of an asphalt modifying agent capable of improving low-temperature properties, post-aging low-temperature properties, modification workability and storage stability of the modified asphalt and an asphalt composition containing the same.